Single dark object appearing to continuously change shape, such that it looked to be almost "tumbling" slowly and in a straight direction of travel. A random glint of light could occasionally be seen as well, like an intermittent reflection of sunlight which added to the tumbling appearance. With clear blue skies the object itself was clearly visible but impossible to say at what height. Adding to the strange appearance was a ring of "distortion" around the object in an area several times larger than the object itself. This distorted area looked similar to the effect of heat radiating in the distance off a hot road, except that it had a distinct "swirling" pattern seemingly generated by the object.